The present invention relates to a vehicle steering wheel. More particularly, the present invention relates to a vehicle steering wheel including a self-regulating electric heating element.
Known steering wheel heating elements include a wire that is either woven into a felt cloth or glued between two felt cloths. When electric current flows through the wire, heat is produced. The wire is connected to a controller that is located in the hub portion of the steering wheel. The controller controls the electric current applied to the wire and, thus, the heat produced by the heating element.
The known steering wheel heating element is tightly wrapped with a leather or leather-like material that forms an outer covering of the steering wheel. The tightly wrapped outer covering compresses the felt material of the known heating element. As a result, the wire of the known heating element can indent the outer covering of the steering wheel and be visible and felt through the outer covering of the steering wheel.
The present invention is a vehicle steering wheel. The steering wheel comprises a central hub portion, a rim portion, and at least one spoke that connects the hub portion to the rim portion. The steering wheel further comprises a self-regulating electric heating element.
A further aspect of the present invention is that the self-regulating heating element includes a cloth substrate that is coated with a positive temperature coefficient (PTC) conductive material. The electrical resistance of the PTC material changes proportionally to the temperature of the PTC material. The heat produced by the heating element decreases as the electrical resistance of the PTC material increases.